So far, there has been no separate study on the titles of Włocławek bishops, but researchers have dealt with this issue in the context of church organization in Kujawy and Gdańsk Pomerania. Initially, the bishops used the titles of Kruszwica, Kujawy and Włocławek alternately. In the 13th century, the Kuyavian-Pomeranian titulary became dominant. There is no clear answer to the question why the title was changed to Pomeranian. These considerations try to look at this problem again, analyzing diplomatic material from the time of the founding of the bishopric until the conquest of Gdańsk Pomerania by the Teutonic Order. The research results indicate the evolution of the title from Włocławek, through Kujawy, to Kujavian-Pomeranian, until the return to the Włocławek title. In diplomatic materials, bishops usually acted as issuers or recipients, which allowed them to determine their preferred titles. It was confirmed that the Włocławek title was used from 1210, while the Kujavian title appeared from 1187. There is no clear interpretation as to why the title was changed. In the papal chancery, it was customary to use the Kujawy and Włocławek titles interchangeably for Włocławek bishops.